ProTon tonometer determination of intraocular pressure in patients with scarred corneas.

ABSTRACT

PURPOSE: To evaluate the measure of intraocular pressure (IOP) in patients with scarred corneas obtained from the affected and non-affected areas. MATERIALS AND METHODS: Eighteen patients with small maculo-leucomatous corneal opacity following microbial keratitis were prospectively included in the study. Goldmann applanation tonometry was done first on the non-affected corneal surface. ProTon tonometry (PT) was then carried out on the same eye, to obtain IOP measurements from the non-affected (PT1) and the affected area (PT2) of the cornea. The IOP measurements were compared using a two-tail paired t test. RESULTS: The mean of IOP measurements of PT 2 and PT1 was 22 mm of Hg (SD +/- 5.2) and 14.8 mm of Hg (SD +/- 5.4), respectively. The higher reading of PT2 was statistically significant ( P < 0.001). The mean Goldmann applanation tonometry was 14.6 mm of Hg (SD 5.4) and it did not differ significantly ( P = 0.86) from the PT1 readings of 14.8 mm of Hg (SD 5.4). CONCLUSION: In patients with maculo-leucomatous corneal opacity, determination of IOP by ProTon tonometer varies from the affected to the non-affected area. The ProTon tonometer overestimates the level of IOP when it is applied to a leucomatous corneal opacity.